Laser Safety for Large Groups

I have two pairs of laser safety goggles. This is sufficient for experiments or demos when it's just a friend and myself. But if I wanted to do a demo for a large group, is there any way to do this economically AND safely?

For public demo's you'd want to be very strict with the safety because of the liability in case something goes wrong. For large non public groups you could be safer by mounting the laser so it doesn't move and shield and terminate the beam.

I once demonstrated my blue laser for a group of 6 people, I ran out of certified goggles but I had some cheap stuff laying around, so I used that. The setup was completely stable, so everybody could take their goggles off to look at the beam. But I was very careful not to place objects in the beam I don't trust. I hand won't give any specular reflection under any circumstances, so it's safe to "touch" the beam. But when they wanted to put a drinking glass in the beam I demanded everybody wore goggles.

So just make sure your setup is stable and the beam out of reach of everyone and the dot safely terminated (a white diffuse reflecting wall is enough). In that case I sometimes don't mind that not everybody is wearing goggles. Unless you have a class 4 laser. But still, beware that this is taking a tiny risk, objects passing the beam (or even more important, people) can be unpredictable.